Field of the Invention
The present invention relates to an object information acquisition apparatus that acquires information on the inside of an object.
Description of the Related Art
In recent years, studies for imaging shape information or physiological information, i.e., functional information on the inside of objects have been pursued in the medical field. As one of such technologies, photoacoustic tomography (PAT) has been proposed recently.
When light such as pulse laser light is irradiated onto a living body serving as an object, acoustic waves (typically ultrasonic waves) are generated while the light is absorbed into living-body tissues inside the object. This phenomenon is called a photoacoustic effect, and acoustic waves generated by the photoacoustic effect are called photoacoustic waves. Since each of tissues constituting an object has a different light energy absorption rate, the sound pressure of generated photoacoustic waves is also different. In the PAT, generated photoacoustic waves are received by a probe, and received signals are mathematically analyzed. Thus, it is possible to form an image of the distribution of optical characteristic values inside an object.
The distribution of optical characteristic values includes, for example, the distribution of sound pressure generated by light absorption (initial sound pressure distribution) or the distribution of light absorption coefficients. In addition, it is also possible to obtain the concentration-related distribution of substances existing inside an object (the distribution of values related to the concentration of the substances) in such a way that a plurality of pulsed light having mutually different wavelengths is applied to calculate a light absorption coefficient for each wavelength.
When an object greatly moves or deforms during the irradiation of pulsed light, distortion or blurring occurs in acquired image data. The occurrence of the distortion or blurring reduces accuracy in calculating distribution related to acquired optical characteristic values, which causes reduction in the reliability of image data. In order to reduce the distortion or blurring, it is necessary to hold an object so as not to move or deform during measurement.
As a related technology, US Patent Application Publication No. 2013/217995 discloses a photoacoustic apparatus that holds the breast serving as an object by a plastic cup and measures the same.
In addition, Japanese Patent Application Laid-open No. 2012-179348 discloses an apparatus provided with a movement mechanism that moves a cup-shaped holding member relative to an object.